TAMPA — Hans Straub, the University of South Florida football strength and conditioning coach, was forced to resign today after a firestorm erupted over a Twitter message he sent Saturday that criticized a former Bulls player who was taken in the NFL draft.

When USF defensive end Aaron Lynch was selected in the fifth round by the San Francisco 49ers, Straub wrote the following on his Twitter feed @CoachStraubUSF: “Thought an organization with 5 Super Bowl titles would have a stricter draft criteria. Clearly, integrity & character are not a priority.’’

During a teleconference of American Athletic Conference coaches, USF coach Willie Taggart said he was “very disappointed’’ by Straub’s actions and added “our administration is dealing with that.’’

Late today, USF athletic director Mark Harlan released the following statement:

“USF Athletics has high expectations for each and every student-athlete, coach and staff member. To that end, I have accepted the resignation of Hans Straub from the position of head strength and conditioning coach. I thank him for his contributions to USF Athletics and wish him well in his future endeavors. A national search for his replacement will begin immediately.’’

Straub didn’t immediately respond to a request for comment.

Straub, hired by Taggart, arrived before last season from Stanford. Taggart had been a Stanford assistant coach under Jim Harbaugh, now head coach of the 49ers, who drafted Lynch. Taggart has widely praised the work of Straub, who most notably has helped add bulk and athleticism to USF’s offensive line during offseason workouts.

Taggart said Straub’s decision to criticize Lynch was a big mistake.

“We always talk to our players about it (Twitter) and how we go about doing it,’’ Taggart said. “If you can’t use it to build a teammate up or our football program up, then there’s no need to be using it at all.

“We always tell our guys to think before you hit send. Hopefully that (message) gets to them and they learn from it.’’

Lynch, who played only one season at USF, originally signed with Notre Dame and was a freshman All-American for the Fighting Irish in 2011. He wanted a return to his home state of Florida, essentially to be near his girlfriend, he later confirmed, so he transferred to USF in the spring of 2012.

After sitting out one year, mandated by NCAA rules, Lynch led the Bulls in sacks (six) and tackles for a loss (12.5), while earning first-team All-American Athletic Conference honors last season. He opted for early entry into the NFL draft and bypassed his senior year.

Lynch, 6-foot-6, 245 pounds, was suspended for the first quarter of USF’s home loss against Louisville on Oct. 26. Taggart called it a violation of team rules and said Lynch had “done something I don’t like.’’

Lynch’s play was inconsistent through much of a season, when his overall discipline came into question after he repeatedly jumped offside and collected a string of personal-foul penalties. During the season, Taggart said Lynch needed to develop a tougher mindset and not get caught up in mistakes.

Taggart said he gave a strong recommendation to Harbaugh for Lynch, who admitted he had underachieved at Notre Dame and USF.

“He worked really hard, but didn’t live up to the expectations that everyone wanted,’’ Taggart said. “But he’s still growing and he’ll continue to grow in a good environment. He needs to grow as a young man and that’s our job as coaches, to help them continue to grow.

“I’m excited I got a chance to coach him for a year. I wish he would’ve come back personally, but I’m excited he got drafted and he gets to do something he wanted to do.’’

Harbaugh, who might consider shifting Lynch to linebacker, the position specialty of 49ers assistant and USF program patriarch Jim Leavitt, said Lynch “needs direction and needs a good structure around him where he’s got guys (around him) that he would look up to and emulate.’’

Lynch described himself as a “first-round talent’’ who has “made some mistakes in my past.’’ 49ers general manager Trent Baalke said Lynch “isn’t a young man that has a rap sheet you’re dealing with (but) he’s made some mistakes and he has to do some things differently.’’